Eddy currents (also called
Foucault currents) are loops of
electric current induced within
conductors by a changing
magnetic field in the conductor, due to
Faraday's law of induction. Eddy currents flow in closed loops within conductors, in planes perpendicular to the magnetic field. They can be induced within nearby stationary conductors by a time-varying magnetic field created by an AC
electromagnet or
transformer, for example, or by relative motion between a
magnet and a nearby conductor. The magnitude of the current in a given loop is proportional to the strength of the magnetic field, the area of the loop, and the rate of change of flux, and inversely proportional to the
resistivity of the material.